[PATCH][EOAN] UBUNTU: SAUCE: Revert "s390/dasd: Add discard support for ESE volumes"

[Dimitri John Ledkov]

BugLink: https://bugs.launchpad.net/bugs/1846219

This reverts commit 7e64db1597fe114b83fe17d0ba96c6aa5fca419a.

Signed-off-by: Dimitri John Ledkov <xnox at ubuntu.com>
---
 drivers/s390/block/dasd_eckd.c | 57 ++--------------------------------
 1 file changed, 3 insertions(+), 54 deletions(-)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index b213c40d1a51..c94184d080f8 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2055,9 +2055,6 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 	if (readonly)
 		set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
 
-	if (dasd_eckd_is_ese(device))
-		dasd_set_feature(device->cdev, DASD_FEATURE_DISCARD, 1);
-
 	dev_info(&device->cdev->dev, "New DASD %04X/%02X (CU %04X/%02X) "
 		 "with %d cylinders, %d heads, %d sectors%s\n",
 		 private->rdc_data.dev_type,
@@ -3691,14 +3688,6 @@ static int dasd_eckd_release_space(struct dasd_device *device,
 		return -EINVAL;
 }
 
-static struct dasd_ccw_req *
-dasd_eckd_build_cp_discard(struct dasd_device *device, struct dasd_block *block,
-			   struct request *req, sector_t first_trk,
-			   sector_t last_trk)
-{
-	return dasd_eckd_dso_ras(device, block, req, first_trk, last_trk, 1);
-}
-
 static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_single(
 					       struct dasd_device *startdev,
 					       struct dasd_block *block,
@@ -4443,10 +4432,6 @@ static struct dasd_ccw_req *dasd_eckd_build_cp(struct dasd_device *startdev,
 	cmdwtd = private->features.feature[12] & 0x40;
 	use_prefix = private->features.feature[8] & 0x01;
 
-	if (req_op(req) == REQ_OP_DISCARD)
-		return dasd_eckd_build_cp_discard(startdev, block, req,
-						  first_trk, last_trk);
-
 	cqr = NULL;
 	if (cdlspecial || dasd_page_cache) {
 		/* do nothing, just fall through to the cmd mode single case */
@@ -4725,14 +4710,12 @@ static struct dasd_ccw_req *dasd_eckd_build_alias_cp(struct dasd_device *base,
 						     struct dasd_block *block,
 						     struct request *req)
 {
-	struct dasd_device *startdev = NULL;
 	struct dasd_eckd_private *private;
-	struct dasd_ccw_req *cqr;
+	struct dasd_device *startdev;
 	unsigned long flags;
+	struct dasd_ccw_req *cqr;
 
-	/* Discard requests can only be processed on base devices */
-	if (req_op(req) != REQ_OP_DISCARD)
-		startdev = dasd_alias_get_start_dev(base);
+	startdev = dasd_alias_get_start_dev(base);
 	if (!startdev)
 		startdev = base;
 	private = startdev->private;
@@ -6513,20 +6496,8 @@ static void dasd_eckd_setup_blk_queue(struct dasd_block *block)
 	unsigned int logical_block_size = block->bp_block;
 	struct request_queue *q = block->request_queue;
 	struct dasd_device *device = block->base;
-	struct dasd_eckd_private *private;
-	unsigned int max_discard_sectors;
-	unsigned int max_bytes;
-	unsigned int ext_bytes; /* Extent Size in Bytes */
-	int recs_per_trk;
-	int trks_per_cyl;
-	int ext_limit;
-	int ext_size; /* Extent Size in Cylinders */
 	int max;
 
-	private = device->private;
-	trks_per_cyl = private->rdc_data.trk_per_cyl;
-	recs_per_trk = recs_per_track(&private->rdc_data, 0, logical_block_size);
-
 	if (device->features & DASD_FEATURE_USERAW) {
 		/*
 		 * the max_blocks value for raw_track access is 256
@@ -6547,28 +6518,6 @@ static void dasd_eckd_setup_blk_queue(struct dasd_block *block)
 	/* With page sized segments each segment can be translated into one idaw/tidaw */
 	blk_queue_max_segment_size(q, PAGE_SIZE);
 	blk_queue_segment_boundary(q, PAGE_SIZE - 1);
-
-	if (dasd_eckd_is_ese(device)) {
-		/*
-		 * Depending on the extent size, up to UINT_MAX bytes can be
-		 * accepted. However, neither DASD_ECKD_RAS_EXTS_MAX nor the
-		 * device limits should be exceeded.
-		 */
-		ext_size = dasd_eckd_ext_size(device);
-		ext_limit = min(private->real_cyl / ext_size, DASD_ECKD_RAS_EXTS_MAX);
-		ext_bytes = ext_size * trks_per_cyl * recs_per_trk *
-			logical_block_size;
-		max_bytes = UINT_MAX - (UINT_MAX % ext_bytes);
-		if (max_bytes / ext_bytes > ext_limit)
-			max_bytes = ext_bytes * ext_limit;
-
-		max_discard_sectors = max_bytes / 512;
-
-		blk_queue_max_discard_sectors(q, max_discard_sectors);
-		blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
-		q->limits.discard_granularity = ext_bytes;
-		q->limits.discard_alignment = ext_bytes;
-	}
 }
 
 static struct ccw_driver dasd_eckd_driver = {
-- 
2.20.1